The Rise of Monoclonal Antibodies and Biosimilars in Oncology

Since the approval of the first recombinant insulin by the US Food and Drug Administration (FDA) in 1982, several biological drugs and medicines were authorized. Thus, beginning the era of undiscovered/infinite possibilities in the field of biopharmaceuticals. To educate the common masses on this little-talked-about concept, we will begin with the most basic knowledge and later dive deep into this mammoth topic of biosimilars, monoclonal antibodies and biopharmaceuticals.

Broadly illustrating, biopharmaceuticals are structurally complex biological molecules that can be composed of nucleic acids, proteins, sugars or complex combinations of these substances and, monoclonal antibodies come under the ambit of protein biopharmaceutical. Similarly, a biosimilar is a type of biological product that is highly similar to an already approved biological drug, also known as a reference product. Understanding these basics is important as these concepts will serve as the basis for the upcoming discussion. Now moving forward to our concerned area i.e. oncology, these products have become an integral part of cancer treatment both as therapeutic agents and as supportive care agents. Thus, becoming dominant in the oncology market.

Introduction 

In oncology, biological medicines are extensively used for treatment, but these products also increase the financial burden on the healthcare sector. As reference products are losing exclusivity rights, this has opened new frontiers for biosimilar medicines in the market. These medicines tend to offer viable and cost-effective treatment options. It should be noted, a biosimilar cannot be considered an identical copy of the originally approved biological product. Minor differences can exist between the biosimilar and the reference product, but it needs to be demonstrated that these differences are not clinically meaningful. Hematopoietic growth factors(epoetin & filgrastim) are used in oncology as supportive treatment, but the introduction of a biosimilar of monoclonal antibodies(mAbs) has just been embarked upon.

mAbs are notably more intricate both in the structural and functional aspects when compared to epoetin and filgrastim. As the door to this innovation has been unlocked, the number of biosimilars available in oncology is likely to increase rapidly, with the therapeutic focus shifting from supportive care for chemotherapy to targeted, potentially life-prolonging or curative monoclonal antibodies (mAbs). Rituximab was the first mAb biosimilar approved by EMA in 2017. Following that, a second rituximab biosimilar, GP2013 (Rixathon), as well as the trastuzumab biosimilar SB3 (Ontruzant) was approved.

Rituximab

It is a genetically engineered mAb used in the treatment of various conditions including cancers especially non-Hodgkin’s lymphoma(NHL) and chronic lymphocytic leukaemia(CLL). It also treats auto-immune disorders such as rheumatoid arthritis, lupus, and multiple sclerosis. The process begins when rituximab binds to a protein called CD20 on the surface of B cells, a type of white blood cell involved in the immune response. By binding to CD20, rituximab helps to destroy the B cells and suppress the immune system. Concerning this mAb, biosimilars to rituximab were developed namely-Blitzima, Truxima, Ruxience, Riximyo, Rixathon and Ritemvia.

FDA-approved mAB biosimilars in oncology:

Trastuzumab

It is a humanised monoclonal antibody used in the treatment of breast cancer that is HER2-positive. It targets and binds to the HER2 protein, which is overexpressed in certain types of breast cancer cells. By binding to HER2, trastuzumab can slow down the growth and spread of cancer cells. Trastuzumab is usually administered intravenously and may be used alone or in combination with chemotherapy. It is typically given as a course of treatment over several months, and the specific dosing regimen will depend on the individual patient’s condition and the stage of their cancer. It has proven to be an effective treatment for HER2-positive breast cancer and has also been approved for use in many countries around the world. Biosimilars of trastuzumab include Herzuma, Kanjinti, Ogivri, Ontruzant and Trazimera.

Bevacizumab

It is a recombinant humanized monoclonal antibody which targets vascular endothelial growth factor (VEGF) and is used to treat various types of cancer. It works by inhibiting the growth of blood vessels that supply nutrients and oxygen to cancerous tumours, thus preventing their growth and spread. Bevacizumab is approved by the U.S. Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancer, non-small cell lung cancer, glioblastoma, metastatic renal cell carcinoma, and cervical cancer. It may be used alone or in combination with other chemotherapy drugs or targeted therapies. Biosimilars of avastin(Bevacizumab) are Mvasi and Zirabev.

EMA-approved mAB biosimilars in oncology:

The Need for Biosimilars in Oncology

A reform is brought in cancer treatment with the introduction of biologics, which are large, complex molecules produced from living cells. Not only are they highly competent at targeting explicit cancer cells but also, they have fewer side effects on patients. However, biologics are expensive, which limits access to these life-saving therapies. Biosimilars are similar to biologics in terms of safety and efficacy but are produced by different manufacturers and at a lower cost, making them an important tool for increasing access to cancer treatment.

The need for biosimilars in cancer is driven by several factors. Firstly, cancer is a disease that affects millions of people worldwide, and the best treatment is biologics which is costly. Biosimilars offer a more cost-effective way to provide these treatments to patients who need them.

Secondly, many biologics have patent protections that prevent competition from generic drugs. Biosimilars, on the other hand, can be developed once the patent on the original biologic has expired, which allows for competition and lower prices.

Finally, biosimilars have the potential to increase the sustainability of healthcare systems by reducing the financial burden of cancer treatment. The cost of cancer treatment is a major concern for patients and healthcare providers alike, and the availability of biosimilars can help to reduce the cost of treatment without sacrificing quality.

Conclusion

With the increase in the number of unknown variations w.r.t diseases, it has become necessary to upgrade our knowledge and expertise in the field of medicine. Biotechnology is proving to be an area of vast possibilities for development and is contributing significantly. The scope for mAb and biosimilars is pushing boundaries for medical improvement. They have provided patients with more treatment options and enhanced access to effective therapies. These developments have also led to a more competitive market, ultimately leading to reduced healthcare costs. As research and development in this field continue, we can expect to see even more promising therapies and improvements in cancer treatment.

Blog by Tamanna Shaikh